From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl0-f70.google.com (mail-pl0-f70.google.com [209.85.160.70]) by kanga.kvack.org (Postfix) with ESMTP id BF8446B0006 for ; Mon, 21 May 2018 18:45:22 -0400 (EDT) Received: by mail-pl0-f70.google.com with SMTP id a5-v6so10778489plp.8 for ; Mon, 21 May 2018 15:45:22 -0700 (PDT) Received: from mga03.intel.com (mga03.intel.com. [134.134.136.65]) by mx.google.com with ESMTPS id q9-v6si14979324plr.144.2018.05.21.15.45.21 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 21 May 2018 15:45:21 -0700 (PDT) Subject: [PATCH 2/5] mm, devm_memremap_pages: handle errors allocating final devres action From: Dan Williams Date: Mon, 21 May 2018 15:35:24 -0700 Message-ID: <152694212460.5484.13180030631810166467.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <152694211402.5484.2277538346144115181.stgit@dwillia2-desk3.amr.corp.intel.com> References: <152694211402.5484.2277538346144115181.stgit@dwillia2-desk3.amr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org List-ID: To: akpm@linux-foundation.org Cc: stable@vger.kernel.org, Christoph Hellwig , =?utf-8?b?SsOpcsO0bWU=?= Glisse , Logan Gunthorpe , linux-mm@kvack.org, linux-kernel@vger.kernel.org The last step before devm_memremap_pages() returns success is to allocate a release action to tear the entire setup down. However, the result from devm_add_action() is not checked. Checking the error also means that we need to handle the fact that the percpu_ref may not be killed by the time devm_memremap_pages_release() runs. Add a new state flag for this case. Cc: Fixes: e8d513483300 ("memremap: change devm_memremap_pages interface...") Cc: Christoph Hellwig Cc: "JA(C)rA'me Glisse" Cc: Logan Gunthorpe Signed-off-by: Dan Williams --- include/linux/memremap.h | 1 + kernel/memremap.c | 8 ++++++-- 2 files changed, 7 insertions(+), 2 deletions(-) diff --git a/include/linux/memremap.h b/include/linux/memremap.h index 7b4899c06f49..44a7ee517513 100644 --- a/include/linux/memremap.h +++ b/include/linux/memremap.h @@ -115,6 +115,7 @@ struct dev_pagemap { dev_page_free_t page_free; struct vmem_altmap altmap; bool altmap_valid; + bool registered; struct resource res; struct percpu_ref *ref; struct device *dev; diff --git a/kernel/memremap.c b/kernel/memremap.c index c614645227a7..30d96be5a965 100644 --- a/kernel/memremap.c +++ b/kernel/memremap.c @@ -296,7 +296,7 @@ static void devm_memremap_pages_release(void *data) for_each_device_pfn(pfn, pgmap) put_page(pfn_to_page(pfn)); - if (percpu_ref_tryget_live(pgmap->ref)) { + if (pgmap->registered && percpu_ref_tryget_live(pgmap->ref)) { dev_WARN(dev, "%s: page mapping is still live!\n", __func__); percpu_ref_put(pgmap->ref); } @@ -418,7 +418,11 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap) percpu_ref_get(pgmap->ref); } - devm_add_action(dev, devm_memremap_pages_release, pgmap); + error = devm_add_action_or_reset(dev, devm_memremap_pages_release, + pgmap); + if (error) + return ERR_PTR(error); + pgmap->registered = true; return __va(res->start);